#1650 Pub pages should display links to the image re-upload Wiki page

[Ahasuerus]

Currently, all Publication pages display an "Upload new cover scan" link. This link always takes you to the ISFDB Wiki's "new image upload" page. We want the software to link either to the new image upload page or to the "image re-upload" page depending on what is in the ISFDB database. The proposed rules are as follows:

• Scenario 1: No current image. Keep he current link to the "new image upload" page. The wording of the link text could be something like "Upload a cover scan".
• Scenario 2: Current image is only used by the current pub. Display a link to the "image re-upload" page. The wording of the link text could be something like "Upload a new version of the cover scan".
• Scenario 3: Current image is used by multiple pubs AND the image is at the current pub's publication tag. Display a link to the "new image upload" page. The wording of the link text could be something like "Upload a new cover scan (current scan is used by other publications)".
• Scenario 4: Current image is used by multiple pubs AND the image is not at the current pub's publication tag AND there is no ISFDB-hosted image with the current pub's publication tag. Display a link to the image re-upload page. The wording of the link text could be something like "Upload a new version of the cover scan".
• Scenario 5: There is an unused ISFDB-hosted image with the currently displayed pub's publication tag. Display a message to that effect and link to the image.

These scenarios may need to be further tweaked before any software changes are implemented.